Measuring head for automotive wheel alignment gauges



Feb. 19, 1952 A H. WOCHNER 2,586,194

MEASURING HEAD FOR AUTOMOTIVE WHEEL ALIGNMENT GAUGES Filed Oct. 25, 1946 3 Sheets-Sheet l II llfllll INVENTOR. L Jere/y iz/c/bze 7 BYOAKM Feb. 19, 1952 H. WOCHNER 2,

MEASURING HEAD FOR AUTOMOTIVE WHEEL ALIGNMENT GAUGES Filed Oct. 25, 1946 5 Sheets-Sheet z Feb. 19, 1952 H. WOCHNER 2,586,194

MEASURING HEAD FOR AUTOMOTIVE WHEEL ALIGNMENT GAUGES Filed Oct. 25, 1946 5 Sheets-Sheet 3 lllllllllllllllllll/ INVENTOR. 17622229 l focfirzer Patented Feb. 19, 1952 MEASURING HEAD FOR AUTOMOTIVE WHEEL ALIGNMENT GAUGES Henry Wochner, Rock Island, 111., assignor to Bear Manufacturing Company, Rock Island, 111., a corporation of Delaware Application October 25, 1946, Serial No. 705,651

2 Claims. (01. 33203)' This invention relates to improvements in a wheel alignment gauge for automobile wheels, and refers specifically to a gauge with which the alignment angles of caster, camber, kingpin inclination and the like can be measured quickly, conveniently and accurately. e

One of the objects of the present invention resides in the provision of a measuring head in combination with a wheel alignment gauge which can be conveniently manipulated and upon which angles can be measured to a fraction of a degree. the measuring mechanism being such that it cannot be easily thrown out of adjustment.

Other objects and advantages of my invention will be apparent from the accompanying drawings and following detailed description.

In the drawings:

Fig. 1 is an elevational view of a wheel alignment gauge made in accordance with the concepts of my invention.

Fig. 2 is a sectional elevational view of the measuring head utilized in conjunction with the wheel alignment gauge.

Fig. 3 is a front elevational view, parts being broken away and parts being shown in section, of the measuring head illustrated in Fig, 2.

Fig. 4 is a face view of the calibrated dial employed in conjunction with the measuring head.

Fig. 5 is a sectional elevational view of a modified form of measuring head.

Fig. 6 is a front elevational view of the head shown in Fig. 5, parts being broken away and parts being shown in section.

In the usual wheeled vehicle such as an automobile, certain angular relationships of the front wheels obtain. These angular relationships are generally known as the steering geometry of the vehicle.

Among the angular relationships which are considered in order to produce a more efiicient support for the load carried by the front wheels, and in order to facilitate steering and control of the front wheels, are the angles of caster, camber, and kingpin inclination. I

Caster is the backward tilt of the front axle whereby the kingpins are so inclined that they are further backward at the top than at the bottom. The purpose of caster is to assist in the tracting of the vehicle, that is, to cause the front wheels of the vehicle to move in a direction parallel to the longitudinal axis of the vehicle or in a straight ahead direction.

Camber .comprises the outward"sloping of the front wheels at the top such that the distance between the tops of the front wheels is greater than the distance between the bottoms of said wheels. The purpose of this relationship is to bring the road contact of the wheels under the point of the load.

Referring particularly to the drawing, I indicates generally a gauge which may be conveniently employed to measure the angles of caster, camber and kingpin inclination. The device I comprises a bar 2 which is preferably of square cross-section and of hollow construction. The bar 2 is preferably constructed of steel, iron or other metallic material. A pair of wheel arms 3are positioned on the bar 2, the arms comprising a hollow square sectioned collar 4 at one end, and a rim-contacting portion 5 at theop'posite end. The arms 3 are adjustable along the length of the bar 2 and may be removably fixed in any desired position along the length of the bar by means of set screws 6.

The bar 2 is rigidly secured intermediate its length to a collar I which comprises a portion of handle 8. The handle 8 also comprises a handgripping member 9 and said handle is adapted to carry at its upper. portion a measuring head ID.

The measuring head It! (Figs. 2, 3 and 4) comprises a housing II having a hollow interior and beingv provided with a circular opening I2. A shaft I3 is positioned in said housing and projects in an angular direction toward the central portion of the opening I2. The lower portion of the shaft I3 is retained ,in a socket I I which is provided in the bottom wall of the housing. A projection I5 extends upwardly from the bottom Wall of the housing adjacent the socket I4, said projection carrying a set screw I6 which is threadedly positioned in the projection. The lower portion of shaft I3 is provided with an annular groove I'I into which the set screw I6 projects. .In this manner the shaft I3 i journalled in thehousing, being free to rotate in the socket I4 but having its longitudinal motion restricted by the set screw I 6. v

A circular dial I8 is adapted to be carried at the opposite end of the shaft I3 and is secured to said shaft by means of screw 22, said dial fitting within the circular opening I2 and, in effect, providing a closure for the housing I I. A scale ring 22' is carried upon the dial I8 and is removably secured thereto by means of fingers I8 which, in turn, are anchored by means of screws I9 upon the dial I8. When the fingers I8 overlap the scale ring 22 and the screws I9 are tightened, the dial and scale ring can be rotated as a unit by means ofknob 20 forming a part of the dial I8. When the screws I9 are loosened and the fingers I8 disengaged from the face of the scale ring, the dial and scal ring may be rotated relative to each other. Calibrated indicia is provided upon the face of the scale ring 22 adjacent its outer periphery forming a scale I 9, and calibrated indicia is also provided upon the face of said ring adjacent its inner periphery forming scale 21. The functionof the. dial-and'scaie ring Will be hereinafter more fully described.

A support 23 is positioned upon the lower wall of the housing II and extends upwardly into the interior of said housing. Arshafttujournalled in the support 23 and carriescat :oneen'daa worm wheel 25. The shaft l3 carriesintermediate its length worm 261whidh operativ ly gages the worm wheel 25 to provide a wormgear.

At the opposite end of shaft 24, an arm 21 is carried which, in turn, supports a-platformi-N. A spirit level 29 is mounted upon the-,platform 28 by means of screws 30. A collar 31 is positioned uponshaft 24 on one side of the block 23 and onthe'opposite side of-said*block-a coil-spring 32 embraces shaft 24- whereby -worm wheel 125- is maintained in operative Position -=withi-respect to worm-'26.

'The" housing 1; I" is provided with *anopening' 33 which :may take *theiorm of an elongated slot. That portionof the housing -'H in which the slot 33 is provided; conforms in'curvature to the path of travel of the spirit level 23 when the arm 2'! v is rotated by shaft 24 whereby the spirit level may be observed exteriorlysofthe' housing.

' The arrangementis-such thatwhen-the housing is in aisubstantially horizontal position; that is, theposition shown #in Figs. -1,2-and-3, and-the arm'2'lis in asubstantially vertical position, the bubble (not-shown) of the spirit level will be centeredwithinsa-id level. Thispositionis hereinafter referred to as its normal position. If the housing is canted about an axis parallel to the shaft 24, the bubble of-the spirit level, obviously, will he-removed from its'eentral position. By manipulation of the dial I 8, shaft -'l-3--ma'y be rotated which in turn rotates wheel 25-and shaft 24, thereby rocking arm 21. By rocking-the arm 21 inythe proper direction, the bubble of the-spirit level may be-brought back to'its central position as ascertained by observation through the slot -33.

When--the deviceis inits normal position, as hereinbefore described, index line '36 inscribed upon housing 1| I, index line 36 inscribedupon dial 1B "and index line 36" corresponding to the zero positions of scales I9 and2l, are all in-coincidence. The relationship of dial l8 and housing I l is a permanent one, but, as "will be hereinafter more fully described, scale-ring 22'-may be moved from its normal position whencaster is measured.

brakes .of the vehicle are locked and thefront of the'front Wheel to be measured'is 'turned'from a straight ahead position toward the centerline of the vehicle through an angle of 20. With the indexes'36, 36' and 36" in registration, the gauge is positioned adjacent the-wheel'with the contacting portions of the wheel arms 3 in contact with the wheel rim, and with thebar 2 disposed -in a verticalplane at "right angles'to the 4 plane of the wheel. The bar 2 may be brought to this position by observation of a spirit level 35 which is positioned upon handle 8 with its longitudinal axis disposed in a substantially horizontal plane, as Viewed in Fig. 1. The bar 2 in all probability will=not be.disposed at right angles "to the ground and, hence, the dial i8 is rotated .until the bubble of the spirit level 29 is brought -"to its central position, as observed through slot 33.

.Thedndexes. 36".aand 36" will then be out of registenwithin'dex 36. Screws l9 are then loosened and fingers 18 are so manipulated as to permit the. rotation ofthescale ring 22' relative to the flialillandsaid ring is rotated to bring the index 36 into registration with index 36. With the parts in this position the screws l9 are tightened t0-10,ck .the scale ring and dial together.

The wheel being measured is then turned back through the straight ahead position and through an angleof 20 in an outwardly direction with respect to the centerline of the vehicle, and with the bar- 2 in-a vertical plane at right angles to the "plane of the wheel, as indicated by the spirit'level'33, the *dial'is turned'until the bubble in spirit level 29 is again centered. The amount of caster indegrees is then read-directly on scale i9opposite index 36.

To measure camber=the dial i8 is set at zero, thatisywith the indexes 36, 3'6 and 36" in alignment, and the gauge is placed against the rim of the wheel to lee-measured. The gauge is positioned in a'verticalplane-"as' indicated by the level -35and the dial is turned untilthe level 29'as seen through slot 33 is centered. The amount of camber is read directly on'the scale 2|.

To measure the kingpin inclination the head It is turned-90 from 'the'position shown in Fig. 1 about the pivot3'4. The dial I8 is adjusted to zero. With the brakes locked the front of the wheel to be measured isturned outwardly from the "straight ahead=position 25. 'The gauge is placed against the rim of the wheel in a vertical positionas shown by the level 35.

The position of the wheel arms with the gauge so adjusted is indicated upon'the rim of thewheel by inscribing a chalk mark or the like at the "positions where the contacting portions 5 touch the rim. The wheel is then turned back through the straight ahead position to an angle of 25 and the gauge is placed on contact with the rim with the contacting portions 5 positioned at the marks previously made. The dial it is then "manipulated until the bubble in the spirit level 29 is brought to its central position. The kingpin inclination in degrees is then read directly on the scale 2| opposite index 36.

Referring particularly to Figs. 5 and 6, a slightly modified measuring head'3'l is shown. The head 37 comprises a casing 38 provided with a circular opening 39. A shaft 40 is journalled at its lower end in asocket 4| provided in the bottom wall of the casing. A set screw 42 is threadedly positioned in a projection 43 formed upon the lower wall of the-casing. Shaft 40 is provided with an annular groove 44 into which the set screw 42 is adapted to be positioned whereby to permit rotatable movement of the shaft 40 and prevent axial movement thereof. A dial 45 is carried at the Opposite end of the shaft 40, said dial being identical with the dial l8 hereinbefore described and having a;sca1e ring mounted thereonsimilar to .scaleringf22'. The dial 45 issecuredto the end of the shaft 40 by means of a screw or the like 46 which may be tightened to cause the dial and shaft'to move as a unit. Similar to the dial I8,

the dial 45 comprises, in effect, a closure for the opening 39.

A worm 4! is carried intermediate the length of shaft 49 and is adapted to engage with a worm wheel 48 mounted upon shaft 49, which in turn is journalled intermediate its length upon standard 50 mounted within the casing 38. A bevel gear 5! is positioned upon. shaft 49 adjacent one side of standard 50 and a coil spring 52 embraces shaft 49 adjacent the opposite side of said standard whereby to prevent axial movement of the shaft 49. An arm 53 is carried upon the end of shaft 49 and support 54 is mounted upon the upper portion of said arm. The support 54 is adapted to carry a spirit level 55 which is secured to said support by means of screws or the like 55.

A second standard 51 is positioned within the casing 38 and serves as a bearing for shaft 58. A beve1 gear 59 is positioned upon shaft 58 adj acent one side of the standard 51 and a coil spring 60 embraces shaft 59 adjacent the opposite side of the standard 57 whereby axial movement of the shaft 58 is prevented. The bevel gear 59 meshes with bevel gear 5| whereby both shafts 49 and 58 move in unison. An arm (ii is carried at the end of shaft 58 and a support 62 is mounted upon the upper end of said arm. The spirit level 63 is mounted upon the upper portion of support 62 and is secured thereto by means of screws 64 or the like.

An opening 65 is provided in the casing 38 adjacent the path of travel of the spirit level 55 whereby the bubble (not shown) of said spirit level may be observed exteriorly of the casing. Similarly an opening 65 is provided in the casing adjacent the path of travel of spirit level 63 whereby the bubble in said level may also be observed.

The measuring head 31 is adapted to be utilized in conjunction with the gauge I and is positionable upon the handle 8. As will be hereinafter more fully described, it is not necessary for the measuring head 31 to be rotated in order to measure kingpin inclination of the wheels of an automotive vehicle as was the case with the measuring head l0. Consequently, the head 31 is mounted upon the handle 8 in a fixed relationship with respect to said handle, the head 31 being positioned upon the handle with the relativeparts thereof in the same location as is the case with the head l0 as viewed in Fig. 1.

The measuring caster and camber, the mechanism comprising the measuring head 31 is manipulated in conjunction with the remaining instrumentalities of the gauge 1 in a manner similar to that hereinbefore described in conjunction with the use of the measuring head !0. When measuring these two geometric relationships, the movement of the dial 45 is correlated with respect to the position ofthe bubble in the spirit level 55.

However, when kingpin inclination is to be measured, it is not necessary to rotate the head 31 with respect to the remaining instrumentalities comprising the gauge l as was the case when the head It was used. To measure kingpin inclination using the head 31, the various steps hereinbefore described are followed in making such measurement with the exception that the readings upon the dial 45 are correlated with respect to the position of the bubble in the spirit level 63. It will be noted that when the head 31 is in its normal position, the spirit level 03 will be in the same relative position as was the spirit level 29 when the head was rotated at 90 to the position illustrated in Fig. 1.

It will be seen that herein is provided a gauge for measuring various of the steering angles" of an automotive vehicles wheels which is rugged and strong, the operative mechanism being completely enclosed so as to minimize the possibility of breakage of the delicate spirit levels used with such devices, and tending toward the prevention of the mechanism being thrown out of adjustment. In addition, a. gauge is provided wherein a relativel large space is provided for each de gree on the scale. Although worm gears are shown and described, it is to be understood that other type gear, sprocket, or cable reducing mechanism can be employed without departing from the fundamental concept or my invention.

I claim as my invention:

1. In combination with an automobile wheel alignment gauge of the type having a handle, a bar carried by said handle and wheel arms carried by said bar for contacting portions of an automobile wheel, of a spirit level carried by said handle with its axis at substantially right angles to the plane of said bar and said wheel arms, a measuring head carried by said handle comprising a housing, a shaft rotatably carried in said housing, a dial carried upon said shaft, an index carried by said housing, a scale ring carried by said dial and movable relative thereto, means upon said dial for securing the dial and scale ring together as a unit, calibrated indicia carried on said scale ring and readable' exteriorly of said housing, a worm carried by said shaft within said housing, a rockable spirit level support comprising a worm wheel engageable with said worm, said support being rockable in a plane substantially parallel to the plane of said bar and said wheel arms, a spirit level carried upon said support whereby rotation of said dial rocks said spirit level in a plane substantially parallel to the plane of said bar and said wheel arms.

2. In combination with an automobile wheel alignment gauge of the type having a handle, a bar carried by said handle, and wheel arms carried by said bar for contacting portions of an automobile wheel, of a spirit level carried by said handle with its axis at substantially right angles to the plane of said bar and said wheel arms, a measuring head carried by said handle comprising a housing having an opening, a shaft rotatably mounted in said housing, a dial carried upon said shaft and comprising a closure for said opening, calibrated indicia carried upon said dial, a spirit level mounted in said housing and tiltable in a plane parallel to the plane of the bar, and means connecting said shaft and said tiltably mounted spirit level whereby said spirit level is tilted by rotation of said dial.

HENRY WOCHNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,931,490 Fisher Oct. 24, 1933 2,206,817 Mann July 2, 1940 2,207,410 OKeefe July 9, 1940 2,235,321 Krumm Mar. 18, 1941 FOREIGN PATENTS Number Country Date 11,094 Great Britain 1905 317,275 Germany Dec. 13, 1919 

